/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */

const Crypto = {};

(function () {
	var base64map = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

	// Crypto utilities
	var util = (Crypto.util = {
		// Bit-wise rotate left
		rotl: function (n, b) {
			return (n << b) | (n >>> (32 - b));
		},

		// Bit-wise rotate right
		rotr: function (n, b) {
			return (n << (32 - b)) | (n >>> b);
		},

		// Swap big-endian to little-endian and vice versa
		endian: function (n) {
			// If number given, swap endian
			if (n.constructor == Number) {
				return (util.rotl(n, 8) & 0x00ff00ff) | (util.rotl(n, 24) & 0xff00ff00);
			}

			// Else, assume array and swap all items
			for (var i = 0; i < n.length; i++) n[i] = util.endian(n[i]);
			return n;
		},

		// Generate an array of any length of random bytes
		randomBytes: function (n) {
			for (var bytes = []; n > 0; n--) bytes.push(Math.floor(Math.random() * 256));
			return bytes;
		},

		// Convert a string to a byte array
		stringToBytes: function (str) {
			var bytes = [];
			for (var i = 0; i < str.length; i++) bytes.push(str.charCodeAt(i));
			return bytes;
		},

		// Convert a byte array to a string
		bytesToString: function (bytes) {
			var str = [];
			for (var i = 0; i < bytes.length; i++) str.push(String.fromCharCode(bytes[i]));
			return str.join('');
		},

		// Convert a string to big-endian 32-bit words
		stringToWords: function (str) {
			var words = [];
			for (var c = 0, b = 0; c < str.length; c++, b += 8) words[b >>> 5] |= str.charCodeAt(c) << (24 - (b % 32));
			return words;
		},

		// Convert a byte array to big-endian 32-bits words
		bytesToWords: function (bytes) {
			var words = [];
			for (var i = 0, b = 0; i < bytes.length; i++, b += 8) words[b >>> 5] |= bytes[i] << (24 - (b % 32));
			return words;
		},

		// Convert big-endian 32-bit words to a byte array
		wordsToBytes: function (words) {
			var bytes = [];
			for (var b = 0; b < words.length * 32; b += 8) bytes.push((words[b >>> 5] >>> (24 - (b % 32))) & 0xff);
			return bytes;
		},

		// Convert a byte array to a hex string
		bytesToHex: function (bytes) {
			var hex = [];
			for (var i = 0; i < bytes.length; i++) {
				hex.push((bytes[i] >>> 4).toString(16));
				hex.push((bytes[i] & 0xf).toString(16));
			}
			return hex.join('');
		},

		// Convert a hex string to a byte array
		hexToBytes: function (hex) {
			var bytes = [];
			for (var c = 0; c < hex.length; c += 2) bytes.push(parseInt(hex.substr(c, 2), 16));
			return bytes;
		},

		// Convert a byte array to a base-64 string
		bytesToBase64: function (bytes) {
			// Use browser-native function if it exists
			if (typeof btoa == 'function') return btoa(util.bytesToString(bytes));

			var base64 = [],
				overflow;

			for (var i = 0; i < bytes.length; i++) {
				switch (i % 3) {
					case 0:
						base64.push(base64map.charAt(bytes[i] >>> 2));
						overflow = (bytes[i] & 0x3) << 4;
						break;
					case 1:
						base64.push(base64map.charAt(overflow | (bytes[i] >>> 4)));
						overflow = (bytes[i] & 0xf) << 2;
						break;
					case 2:
						base64.push(base64map.charAt(overflow | (bytes[i] >>> 6)));
						base64.push(base64map.charAt(bytes[i] & 0x3f));
						overflow = -1;
				}
			}

			// Encode overflow bits, if there are any
			if (overflow != undefined && overflow != -1) base64.push(base64map.charAt(overflow));

			// Add padding
			while (base64.length % 4 != 0) base64.push('=');

			return base64.join('');
		},

		// Convert a base-64 string to a byte array
		base64ToBytes: function (base64) {
			// Use browser-native function if it exists
			if (typeof atob == 'function') return util.stringToBytes(atob(base64));

			// Remove non-base-64 characters
			base64 = base64.replace(/[^A-Z0-9+\/]/gi, '');

			var bytes = [];

			for (var i = 0; i < base64.length; i++) {
				switch (i % 4) {
					case 1:
						bytes.push((base64map.indexOf(base64.charAt(i - 1)) << 2) | (base64map.indexOf(base64.charAt(i)) >>> 4));
						break;
					case 2:
						bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0xf) << 4) | (base64map.indexOf(base64.charAt(i)) >>> 2));
						break;
					case 3:
						bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0x3) << 6) | base64map.indexOf(base64.charAt(i)));
						break;
				}
			}

			return bytes;
		}
	});

	// Crypto mode namespace
	Crypto.mode = {};
})();

module.exports = Crypto;
